Many devices are known in the prior art for testing the hardness and/or softness of material. Some prior art systems are for the specific purpose of testing the hardness or softness of paper web material and rolls formed therefrom.
A search of the prior art located the following United States patents: U.S. Pat. No. 3,194,061, issued Jul. 13, 1965, U.S. Pat. No. 4,182,163, issued Jan. 8, 1980, U.S. Pat. No. 3,540,270, issued Nov. 17, 1970, U.S. Pat. No. 4,435,976, issued Mar. 13, 1984, U.S. Pat. No. 4,159,640, issued Jul. 3, 1979, U.S. Pat. No. 5,062,293, issued Nov. 5, 1991, U.S. Pat. No. 4,945,490, issued Jul. 31, 1990, U.S. Pat. No. 5,079,728, issued Jan. 7, 1992, U.S. Pat. No. 3,822,588, issued Jul. 9, 1974, and U.S. Pat. No. 4,667,509, issued May 26, 1987.
It is often desirable to test the firmness of individual rolls of toilet tissue, toweling and the like to provide the manufacturer or others assurance that the roll firmness meets established specifications. The devices disclosed in the patents indicated above are, for the most part, totally inappropriate for such purpose. Furthermore, prior art approaches are characterized by their relative complexity and high expense. In addition, testing of individual rolls is complicated by the fact that such rolls are often produced in different diameters. Differences of diameter must be taken into account when the test is made. The prior art approaches do not address this problem.